In the field of standard homogenizing where high pressure in a range of from 500 p.s.i. up to 12,000 p.s.i. is the source of energy, as distinguished from high speed mixers and colloid mills where no appreciable pressure is utilized, problems are encountered. One such problem is the occurrence of radial divergence of fluid flow and is due in part to the fact that almost all conventional valves of any consequence are of circular cross section and are made with an inner diameter of one size and an outer diameter of a larger size.
Typical of standard valves of this construction are homogenizing structures disclosed in U.S. Pat. Nos. 2,504,678; 2,242,809; 2,304,689; 2,882,025; 2,137,854.
Fluid material under pressure is fed through a hole in a valve seat element and flow is restricted by a matching valve member having a surface parallel to that of the valve seat. Pressurized fluid flows from the hole, commonly referred to as the inner aperture diameter, outwardly to become impacted against an impingement ring which surrounds an outer larger diameter of the aperture, and a radial divergence of flow takes place. This radial divergence of flow produces second and third degree phenomena in the pressure gradients which vary with the ratio of the outer diameter of the aperture to its inner diameter. This may affect any particular material being processed at any given flow rate with troublesome results.
Because of the conditions which may result from radial divergence, it is virtually impossible to extrapolate the results and behavior obtained in a valve with one size and configuration to that of another similar configuration of different size and flow rate requirements. In some cases, similar effects on the material being processed can be obtained from different output, but only after trial and error procedures which may be time-consuming and expensive, and in some instances, impractical. Another problem which is believed to be due to radial divergence of flow has to do with the need for supplying a conduit system, and a controllable back pressure must be maintained to obtain homogenizing efficiency of a satisfactory nature. Still another problem is the drop in efficiency at very high and very low flow rates.